FIG. 24 shows a conventional cellular phone 500.
A terminal IF (interface) unit 510, a radio communication control unit 520 and a radio communication unit 530 are provided to the conventional cellular phone 500. The terminal IF unit 510 performs interface with a user of the cellular phone 500. The radio communication control unit 520 performs communication control of the whole cellular phone, data conversion and data processing based on protocol. The radio communication unit 530 modulates and demodulates data to enable radio communication. The radio communication unit 530 supports the physical layer (layer 1), which is the lowermost layer of seven layers defined by OSI (Open Systems Interconnection). A confidentiality processing unit 540 is provided to the radio communication unit 530. The confidentiality processing unit 540 encrypts or decrypts data of the physical layer to be processed by the radio communication unit 530. As the data sent/received by an antenna 541 is encrypted by providing the confidentiality processing unit 540, wiretappers are prevented from obtaining any significant information unless the ecryption codes are broken.
The conventional cellular phone 500 has the confidentiality processing unit 540 within the radio communication unit 530. Accordingly, the data to be processed by the confidentiality processing unit 540 is stored in the physical layer (layer 1). At the physical layer, it is impossible to discriminate data between user data and control data. Data sent/received by the cellular phone includes various kinds of data such as user data or signaling data, and it is required to perform data confidentiality processing based on the data kinds, or to ensure data integrity depending on the significance of the data. As shown in the conventional architecture, since the confidentiality processing unit 540 is provided to the layer 1, the data cannot be performed the confidentiality processing nor the integrity processing based on the data kind because it is impossible to discriminate the data kinds at the layer 1.
Further, the conventional confidentiality processing has been performed by generating a random number sequence synchronously with inputting data and by performing an XOR operation of the data and the random number sequence synchronously with inputting the data.
Yet further, the conventional integrity processing has been performed by generating a message authentication code for each data or checking integrity of the data for each data.
A preferred embodiment of the present invention aims to perform high-speed data confidentiality and integrity processing.
Further, another objective of the preferred embodiment of the present invention is to perform the data confidentiality and integrity processing at a higher layer equal to or greater than layer 2 (data link layer) of the seven layers of the OSI.
Yet further, another objective of the preferred embodiment of the present invention is to perform the data confidentiality and integrity processing without loading on the central processing unit and the bus.